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Handle setcc <global*>, 0 instructions, Global pointers are never null!

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2582 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2002-05-09 20:11:54 +00:00
parent 0aa7cd605d
commit 53a5b57737
1 changed files with 18 additions and 4 deletions
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22
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -343,17 +343,31 @@ Instruction *InstCombiner::visitXor(BinaryOperator *I) {
return Changed ? I : 0;
}
// isTrueWhenEqual - Return true if the specified setcondinst instruction is
// true when both operands are equal...
//
static bool isTrueWhenEqual(Instruction *I) {
return I->getOpcode() == Instruction::SetEQ ||
I->getOpcode() == Instruction::SetGE ||
I->getOpcode() == Instruction::SetLE;
}
Instruction *InstCombiner::visitSetCondInst(BinaryOperator *I) {
if (I->use_empty()) return 0; // Don't fix dead instructions...
bool Changed = SimplifyBinOp(I);
// setcc X, X
if (I->getOperand(0) == I->getOperand(1)) {
bool NewVal = I->getOpcode() == Instruction::SetEQ ||
I->getOpcode() == Instruction::SetGE ||
I->getOpcode() == Instruction::SetLE;
AddUsesToWorkList(I); // Add all modified instrs to worklist
I->replaceAllUsesWith(ConstantBool::get(NewVal));
I->replaceAllUsesWith(ConstantBool::get(isTrueWhenEqual(I)));
return I;
}
// setcc <global*>, 0 - Global value addresses are never null!
if (isa<GlobalValue>(I->getOperand(0)) &&
isa<ConstantPointerNull>(I->getOperand(1))) {
AddUsesToWorkList(I); // Add all modified instrs to worklist
I->replaceAllUsesWith(ConstantBool::get(!isTrueWhenEqual(I)));
return I;
}